FN及其受体整合素α5在小鼠肾小体发育过程中的表达

Expression of FN and integrin α_5 in the developmental process of murine renal corpuscles

目的观察细胞外基质的重要成分纤维粘连蛋白(FN)及其受体整合素5α在小鼠肾小体发育过程中的表达,探讨它们在肾小体发育过程中的作用和相互之间的关系。方法选取胚龄(E)12、14、16、18d和生后日龄(P)1、3、7d共7组小鼠,每组8只,E12d组小鼠取全胚,其余各组小鼠取左侧肾脏经固定、脱水、定向包埋等步骤后制备石蜡切片,行免疫组织化学染色和体视学分析。取各组小鼠右侧肾脏液氮速冻后,-80℃保存,用免疫印迹方法检测FN和整合素5α的含量。结果免疫组织化学染色结果显示,FN表达于除逗号小体以外的各期肾小体基膜。整合素α5在不同胚日龄小鼠肾小体的上皮细胞和内皮细胞都有一定程度表达。体视学测量结果显示FN表达的面密度值和整合素5α表达的体密度值都随着肾脏的发育逐渐增大。免疫印迹结果显示,FN和整合素5α蛋白的含量都随肾脏的发育而逐渐增加。结论 FN和整合素α5在小鼠肾小体的发育和成熟过程中具有一定的时空性表达,对肾小体基膜的发育起一定作用。

Objective Fibronectin （FN） is one of the important extracellular matrixes （ECM）, and integrin α5 is a major receptor of FN. To clarify the function and the relationship of FN and integrin α5 in murine nephrogenesis, the expressions of FN and integrin α5 in renal corpuscles were observed. Methods Fifty-six embryos and neonatal Kunming mice were divided into seven groups as follows （8 each） ： embryonic age 12 days （E12d）, E14d, E16d and E18d, and postnatal 1 day （Pld）, P3d and P7d groups. In E12d group, the whole embryos were used, while the left kidney was harvested in other groups. They were embedded with paraffin after fixation and dehydration. Attention should be paid to keep the kidney tissue in a suitable position during embedment. Paraffin sections were made, and the expressions of FN and integrin α5 were detected by immunohistochemical staining and analyzed with stereological method. The right kidneys were taken from all the mice exeept E12d group, and they were rapidly frozen with liquid nitrogen, and then preserved at -80℃. The contents of FN and integrin α5 were detected by Western blotting. Results a） Immunohistochemical staining showed that FN was expressed in the basement membrane at any developmental stage of the kidney, with the exception of comma-shaped bodies. Integrin α5 was partially expressed in epithelial cells and endothelial cells at every stage of nephrogenesis; b） stereological measurement showed that the surface density of FIN and the volume density of integrin α5 increased gradually during the period of nephrogenesis; c） Western blotting showed that the contents of FN and integrin α5 increased gradually during the period of nephrogenesis. Conclusion FN and integrin α5 may have certain chronological and spatial sequence in expression during the period of nephrogenesis, implying that they may play an important role in the development of renal corpuscles basement membrane.